Last night when entering a compact machine I received an Internal Server Error message. Upon rejoining the server, I noticed that I was in the compact machines world, but not in a compact machine. From there I started falling to my death as I was just somewhere randomly in the world nowhere near the machines boundaries. Luckily I could fly, but still almost died from the void damage (was -200-ish down).

Can we get a check in place when a client joins the server and are in the compact machine world to see if they are within the machine boundaries? If they are not within the boundaries, I believe they should either be moved to one of the machines, or sent back to wherever they originally came from.

Which version were you using? You should get teleported to a valid spawnlocation once you've left the room boundaries.

Sorry, I am using 1.12 currently.

This can only happen the first time a player enters the dimension and a crash at the same time is pretty rare. Won't fix unless it pops up again.